At present, in AC power network, a power transfer coefficient from a bus injection power to a branch transferred power is not only needed to be used in the normal state regulation of real-time operation to ensure the real-time economy, but also is needed to be used in the failure state control to satisfy the real-time requirement of power network security and stability. Therefore, the power transfer coefficient from the bus injection power to the branch transferred power is an important tool that allows the operation of AC power network more secure, stable and economical.
The existing methods for obtaining a set of power transfer coefficients in AC power network are based on the set of buses power balancing equations neglecting transmission losses and discarding reference-bus power balancing equation (the reference-bus is an artificially specified bus at which bus voltage angle is set to zero). By the existing methods, a set of power transfer coefficients from the bus injection power of each bus to the branch transferred power of each branch in AC power network varies with the change of the artificially specified reference-bus, is not unique (that is it doesn't comply with the uniqueness theorem for electromagnetic field in circuits), and the power transfer coefficients from the reference-bus injection power of power sources and loads to the branch transferred powers of individual branches are constantly zero (that is the power sources and loads connected to reference-bus don't follow electric circuit laws). In addition, the existing methods for obtaining a set of power transfer coefficients from buses injection powers to branch transferred power in AC power network are implemented either by assuming that the bus injection power of each load is invariant, or by assuming that the bus injection power of each power source is invariant, which are not applicable to the practical situation that the bus injection powers of power sources and loads change at the same time. For the existing methods for obtaining a set of power transfer coefficients in AC power network, the obtained results thereof not only don't comply with the uniqueness theorem for electromagnetic field in circuits, but also don't follow electric circuit laws, are not applicable to the practical situation that the power network is lossy and bus injection powers of power sources and loads change at the same time, and thus fail to truly reflect the substantive characteristics of the power transfer from bus injection powers to branch transferred powers.